How to 3D Print Your Dog
This is Marley; she’s your classic rock digging dog, the first pup you adopt in Loot Hound. At some point after production of the game had finished, we thought it would be an interesting idea to give the digital dog a physical form. Utilising the taboo alchemy of 3D printing, we constructed a dog shaped vessel with which to attach a similarly shaped soul, and bring our girl to life at last.
Page to Print
First, before we started modelling our character in 3D, we decided it would be best to simplify Marley’s design. We were unfamiliar with the printing process, and it’s various print check requirements; who knows what issues might arise due to some superfluous furry detailing?
With a (ruff) design at the ready, we brought our sketch into Blender and meshed up our Marley.
In order to make it economically compatible for certain types of 3D printing, we needed to hollow out her body. This can be a bit fiddly even with Blender’s handy solidify modifier. The “walls” of the model typically need to be around 7mm thick for most objects to be printed reliably. She also needed a wee bum hole of around 2mm to give that extra material an escape route.
One type of 3D print material (full colour sandstone) is mixed with ink and printed in colour. Obviously that’s something we wanted to try out because it’s what makes Marley into the happy spud she is.
We requested our fellow Whisky Bond residents Step3D to print a prototype of our model, and voila, our first ever print! It’s very light, and on close inspection you can see/feel the “steps” that come with the layered printing process. Imagine a bunch of horizontal slices piled on top of each other until the model takes shape. The print is partially hollowed as part of the process with this material, but strengthened by a grid like structure of very thin walls.
One handy tip for 3D printing is that not all of the geometry need be part of the same mesh. Having separate objects intersect with each other (such as the collar tag and the body) is perfectly acceptable. Non manifold geometry (holes in the mesh, i.e. not “watertight”), however, is not, neither is having too many, or too severe, non-planar faces.
Shortly after we committed to an order of a full colour sandstone printed model from Shapeways.
This print is heavier and feels rough as you might expect of sandstone, hard and brittle, like a stoney dog biscuit. The material requirements demand her to have a larger escape hole, so we amputated her bottom.
We found out, perhaps obvious to some, that 3D print colours should be treated just like regular ol’ colour printing.
In person, Marley’s colours are less vibrant than in these images, we discovered that this is quite normal but can be mitigated if you give CMYK respect. More colours mixed, like any ink or paint, produces darker, muddier hues. We also learned from various tip-giving websites to avoid mixing black ink with any of the other colours.
Things Get Meshy
Another more important issue, but related to the mesh, is how Blender exports were interpreted by Shapeways. Upon upload to the site, we repeatedly received vague error messages that were due to the size of the exported mesh. It turns out that Blender has this handy habit of changing the scale of our objects during export, which means Marley was too small for Shapeways to comprehend.
We found a couple solutions to this problem; one is to scale the size of the model in blender by x10, 100, -1000, or until Shapeways starts recognising it’s existence during the upload process. It was definitely a trial and error process for us, and doesn’t seem to make a whole lot of sense, but if it works, we ain’t complaining.
Another fix we tried was checking the export settings for the inconspicuous button in the image above. It’s sole purpose seems to be for trolling unsuspecting users like us. Fortunately this only applies when exporting the model in this particular format (.FBX).
We had similar problems with scale when importing FBX files into Unity. To avoid issues we have to deactivate this button every single time we export a model. Blender is a mischievous software, one that we recommend, but it’s not without it’s perplexities.
With all these issues figured out from our first print, we can confidently move forward into building our dog army. 2017 should prepare itself for a right good licking!